Question

In 10 ​minutes, a conveyor belt moves 300 pounds of recyclable aluminum from the delivery truck to a storage area. A smaller belt moves the same quantity of cans the same distance in 30 minutes. If both belts are​ used, find how long it takes to move the cans to the storage area.

Answer 1

Let us calculate the speed of each conveyor belt. The bigger one does 300 pounds in 10 minutes, hence its speed is 300 pounds/ 10 minutes=30 pounds/min. The smaller one needs 30 minutes, hence its speed is 300 pounds/ 30 minutes=10 pounds/min. We see that the total speed of both machines if they work together is 30+10=40 pounds/min. We have then that the two machines together can transfer 300 pounds in 300/40=7.5 minutes.